Is Tracking Error Bad?

Is High Tracking Error a Bad Thing?

Although high tracking error sounds like a bad thing, tracking error is simply a way to quantify risk—not place a value judgement on it. To help address any misconceptions, let’s define tracking error first and then talk about why understanding it is important. 

What Exactly is Tracking Error?

Managed portfolios behave slightly differently from their benchmark indexes on a day-to-day, month-to-month, and year-to-year basis—even portfolios designed to perfectly “track” their benchmark. In other words, there is a “wobble” in the portfolio’s performance in relation to its benchmark. Tracking error measures the degree of this wobble.

Tracking error is formally defined as the standard deviation of the difference between the returns of the portfolio and the returns of the benchmark—or the dispersion of the excess portfolio returns compared to its benchmark.

Tracking Error = Standard Deviation of (Portfolio returns – Benchmark returns)

Tracking error is typically expressed both as an annualized number and as a percentage. So, for example, we could say a portfolio has a tracking error relative to its benchmark of 1% per year. For a portfolio with a normal distribution of excess returns and an annualized tracking error of 1%, we would expect its return to be within 1% of its benchmark return approximately every two out of three years.  

Why is Tracking Error Important?

Tracking error is an important notion in portfolio management because it distills all the differences between the portfolio and benchmark into a single number. 

Tracking error also plays an important client communication role, in that it sets appropriate expectations for how large the difference between the benchmark and the portfolio return will likely be.  

Active portfolio managers typically show a large tracking error because they seek excess return (alpha) through their active positioning versus the benchmark. With active managers, it’s common to see return differences of more than 2% in a month, which leads to an annualized tracking error of 5% as seen below.

Tracking Error Graph 1

Passive managers, on the other hand, usually seek to demonstrate low tracking error, 0.5% shown below, with return differences coming from the frictions of implementation, trading and liquidity costs, imprecise cash flows, tax costs, etc.  


Tracking Error Graph 2

The above graph show examples of tracking error visually. Here, we are plotting monthly return differences, each corresponding to a different level of tracking error. In these graphs, we assume no alpha and simulate the return differences from a normal distribution. Tracking Error = 0.5%: this is an index fund. Return differences each month are very small.

Bottom Line

Tracking error can be an important consideration when choosing an investment manager. The smaller the number, the more tightly bound the portfolio return should be to the benchmark return. However, the degree of tracking error that an investor is willing to accept is a personal choice and depends on overall investment objectives. 
Potential Parametric Solution:
Parametric’s Custom CoreTM Strategies allows investors to take charge of their passive mandates. Since our portfolios are held as separate accounts, we have the ability to customize to the needs of the client. Investors can select from a wide range of benchmarks and then tailor their exposure to incorporate their unique objectives.

Rey Santodomingo

Rey Santodomingo - Managing Director of Investment Strategy

Mr. Santodomingo is responsible for all aspects of Parametric’s Tax-Managed Equity Strategies. As one of the primary strategists for Custom Core™, he works closely with taxable clients and advisers to design, develop and implement custom portfolio solutions.

The views expressed in these posts are those of the authors and are current only through the date stated. These views are subject to change at any time based upon market or other conditions, and Parametric and its affiliates disclaim any responsibility to update such views. These views may not be relied upon as investment advice and, because investment decisions for Parametric are based on many factors, may not be relied upon as an indication of trading intent on behalf of any Parametric strategy. The discussion herein is general in nature and is provided for informational purposes only. There is no guarantee as to its accuracy or completeness. Past performance is no guarantee of future results. All investments are subject to the risk of loss.